1. Field of the Invention
The present invention relates to a backlight module, and especially to a backlight module having a positioning structure for a light guide plate, and a display comprising the same.
2. Description of Related Art
With the development trend of miniaturization and lightweight of electronic device, the volume of backlight module in a display is adapted to this trend. A backlight module is an indispensable element of a display device, usually composed of a backboard, a light guide plate, a light source and multiple optical films, to scattering light evenly.
In the current backlight module, the light guide plate is typically engaged with a backboard or plastic frame, or arranged on the backboard by a copper pillar. The light guide is susceptible to thermal deformation due to its thermal expansion property, thereby detrimentally affecting the light guide effect of the light guide plate. In order to avoid damage of the light guide plate due to thermal expansion, a sufficient space around the light guide plate is usually reserved for its expansion and contraction. However, this can result in an undesirably long distance between the light guide plate and the light source, which reduces the light entrance efficiency, and thereby increases the brightness variability of the backlight module.
The distance between the light source and the light guide plate can be reduced to improve the light entrance efficiency, but with reduction of the space for expansion and contraction, the light source is under the risk of being crushed by the light guide plate. Also, the thermal expansion of the light guide plate will probably cause a large amount of displacement of the light guide plate, resulting in scratch of the light guide plate or pressing the glass to bulge outward to deform the optical layer, thereby causing top white light leakage and bad aesthetic.
In view of the above problems, what is needed is to develop a backlight module, which not only can effectively position the light guide plate, but also can control the expansion and contraction of the light guide plate without affecting the light entrance efficiency, to avoid damage to the backlight module.